Can any one give me tips on how to make a certain material with nodes?
It seems you want to draw triangles going outside a point, lots of them. The basic setup is this:


By fiddling with those values you can get various shapes:
 
Then you can use a Voronoi texture to get random positions:
 
Instead of using Voronoi you might want to have a simple mathematical formula to calculate which cell you are in and where's that cell's center - then you can try some tricks like add a transparent color to the color ramp (where the black is currently), and use Alpha as a check if the pixel is &quot;empty&quot; - if so, draw a triangle from the nearest cell. Or you can just use that alpha to merge multiple such textures together:

You could make the stars less regular by e.g. multiplying the gradient texture by the number of triangles, and rounding it to get the triangle number, then e.g. do a modulo 2 to detect if the triangle is odd - if so, draw a black (transparent) pixel - or even better, calculate the distance to the center (the middle line) of the next triangle, so that you don't draw a black line near the center where the triangles overlap. You could also replace Voronoi with mathematically defined slopes (&quot;Multiply Add&quot; -&gt; &quot;Greater than&quot;) and allow some triangles to pass it, while some others to not pass it (and then those slopes could be other triangles). Possibilities are endless, though your node count will grow fast.